Suction throttle mechanism of compressor

ABSTRACT

A suction throttle mechanism of a compressor includes a valve body, a valve seat, and a valve housing. The valve housing and the valve seat are formed as separate bodies, and the valve housing and the valve seat are spaced away from each other. The valve housing has guide portions which make sliding contact with the valve body to thereby allow the valve body to move in a contact-separate direction. When the valve body is separated from the valve seat, a fluid flowing from an inlet port toward the valve body through the valve seat passes between the valve seat and the valve housing to enter a suction chamber.

This nonprovisional application is based on Japanese Patent Application No. 2013-272348 filed on Dec. 27, 2013 with the Japan Patent Office, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a suction throttle mechanism of a compressor.

2. Description of the Background Art

A variable-displacement type compressor controlling its displacement is known. Such a compressor includes a suction throttle mechanism. The suction throttle mechanism is disposed in a suction passage between an inlet port and a suction chamber. The suction throttle mechanism varies the opening of the suction passage. When a sucked refrigerant has a low flow rate, noise due to pulsation is likely to occur. The suction throttle mechanism varies the opening of the suction passage depending on the flow rate of a sucked refrigerant to thereby suppress occurrence of pulsation.

As disclosed in Japanese Patent Laying-Open Nos. 2008-196465, 2006-207465, and 2000-136776, a common suction throttle mechanism of a compressor includes a valve body (spool) for opening/closing a suction passage, and tubular guide means (housing or the like) for guiding the valve body. While the valve body is reciprocating, the valve body is guided by the guide means. The valve body is moved away from a valve seat to open a valve hole and thereby allow an inlet port and a suction chamber to communicate with each other through the suction passage. Depending on the amount of displacement (amount of lift) of the valve body, the opening of the suction passage is adjusted.

The compressor disclosed in Japanese Patent Laying-Open No. 2008-196465 includes a housing, a suction passage provided to extend through the housing, and a suction throttle valve disposed inside the suction passage. The suction throttle valve includes a hollow-cylindrical valve housing and a valve body disposed in an internal space (valve chamber) of the valve housing and reciprocating while sliding in contact with the inner peripheral surface of the valve housing. In the sidewall of the valve housing, a communication passage (through hole) is also provided to extend therethrough for allowing the valve chamber and a suction chamber to communicate with each other. A refrigerant flowing from an inlet port into the valve chamber through a valve hole further flows through the communication passage toward the suction chamber. The valve housing has a function for forming the communication passage in addition to a function of guiding the valve body.

In this configuration, an increase of the opening area of the communication passage involves an increase of the size of the through hole provided to extend through the guide means such as the valve housing. This also involves a decrease of the size of a portion (sidewall) of the guide means, namely the portion guiding the valve body. While the aforementioned portion of the guide means that guides the valve body acts as a resistance against the flow of the refrigerant, this portion still requires a certain strength or more. It has conventionally been difficult to decrease the portion of the guide means that guides the valve body, namely to increase the opening area of the communication passage.

An object of the present invention is to provide a suction throttle mechanism of a compressor that has a structure enabling the opening area of the communication passage to be increased.

SUMMARY OF THE INVENTION

A suction throttle mechanism of a compressor based on the present invention includes: a valve seat disposed in a suction passage between an inlet port and a suction chamber of the compressor and formed in a cylindrical shape for passing a fluid through the valve seat; a valve body moving in the suction passage in a contact-separate direction in which the valve body is to contact or separate from the valve seat to thereby adjust an opening of the suction passage; and a valve housing accommodating an urge member urging the valve body toward the valve seat, the valve housing and the valve seat being formed as separate bodies, the valve housing and the valve seat being spaced away from each other, the valve housing having a guide portion sliding in contact with the valve body to thereby allow the valve body to move in the contact-separate direction. When the valve body is separated from the valve seat, a fluid flowing from the inlet port toward the valve body through the valve seat passes between the valve seat and the valve housing to enter the suction chamber.

The present invention can implement a structure that enables the opening area of the communication passage to be increased.

The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing a compressor including a suction throttle mechanism in a first embodiment.

FIG. 2 is a cross-sectional view showing the suction throttle mechanism (closed state) in the first embodiment.

FIG. 3 is a perspective view schematically showing the suction throttle mechanism (opened state) in the first embodiment.

FIG. 4 is a cross-sectional view showing the suction throttle mechanism (full-opened state) in the first embodiment.

FIG. 5 is a cross-sectional view along a line V-V in FIG. 4 as seen in the direction of arrows.

FIG. 6 is a cross-sectional view showing a suction throttle mechanism (full-opened state) in a comparative example.

FIG. 7 is a cross-sectional view along a line VII-VII in FIG. 6 as seen in the direction of arrows.

FIG. 8 is a cross-sectional view showing a suction throttle mechanism (closed state) in a second embodiment.

FIG. 9 is a cross-sectional view showing a suction throttle mechanism (closed state) in a third embodiment.

FIG. 10 is a perspective view schematically showing a suction throttle mechanism (opened state) in a fourth embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments will hereinafter be described with reference to the drawings. Where the number, quantity, or the like is mentioned, the scope of the present invention is not necessarily limited to the number, quantity or the like unless otherwise specified. The same parts and corresponding parts are denoted by the same reference numerals, and a description thereof may not be repeated.

First Embodiment

(Compressor 100)

FIG. 1 is a cross-sectional view showing a variable-displacement-type swash plate compressor 100 (hereinafter referred to as compressor). A suction throttle mechanism 50 of the compressor in the present embodiment (hereinafter referred to as suction throttle mechanism 50) is included in this compressor 100 (as will be detailed later herein). The compressor 100 includes a housing 11 which forms an outer shell of the compressor 100. The housing 11 includes a cylinder block 12, a front housing 13, and a rear housing 14.

To the front side of the cylinder block 12, the front housing 13 is joined. To the rear side of the cylinder block 12, the rear housing 14 is joined. The cylinder block 12, the front housing 13, and the rear housing 14 are fastened together with a bolt 15 which is passed through from the front housing 13 to the rear housing 14.

In the inside of the front housing 13, a crank chamber 16 is formed. The rear side of the crank chamber 16 is closed by the cylinder block 12. In the crank chamber 16, a driveshaft 17, a lug plate 21, and a swash plate 22 are provided. The driveshaft 17 passes through a substantially central portion of the crank chamber 16 and extends in the fore-and-aft direction.

The driveshaft 17 is rotatably supported by a radial bearing 18 provided in the front housing 13 and a radial bearing 19 provided in the cylinder block 12. Located forward of the radial bearing 18 is a shaft seal mechanism 20. The shaft seal mechanism 20 makes sliding contact with the outer peripheral surface of the driveshaft 17. The front end of the driveshaft 17 is coupled through a power transmission mechanism (not shown) to an external drive source.

The lug plate 21 in the crank chamber 16 is fixed to the driveshaft 17, and rotates together with the driveshaft 17. The swash plate 22 is disposed rearward of the lug plate 21. Between the lug plate 21 and the swash plate 22, a hinge mechanism 23 is provided. The swash plate 22 forms a part of a displacement changing mechanism, and is supported in such a manner that the swash plate can slide and can tilt in the axial direction of the driveshaft 17. The swash plate 22 is coupled to the lug plate 21 and the driveshaft 17 through the hinge mechanism 23 so that the swash plate is synchronously rotatable and tiltable.

Between the lug plate 21 and the swash plate 22, a coil spring 24 and a tubular body 25 are provided. The tubular body 25 is freely slidable along the driveshaft 17, and urged rearward by the coil spring 24. The swash plate 22 is constantly pressed by the coil spring 24 and the tubular body 25, in the direction in which the tilt angle of the swash plate 22 is decreased. The tilt angle of the swash plate 22 is the angle formed between a plane orthogonal to the driveshaft 17 and the swash plate 22.

The attitude (position) of the swash plate 22 when the swash plate 22 forms a maximum tilt angle is determined by abutment of a front end 22 a of the swash plate 22 against the lug plate 21. A coil spring 27 and a snap ring 26 are provided rearward of the swash plate 22. The snap ring 26 is mounted on the driveshaft 17. The attitude (position) of the swash plate 22 when the swash plate 22 forms a minimum tilt angle is determined by abutment of the swash plate 22 against the coil spring 27. In FIG. 1, the swash plate 22 indicated by a solid line forms the maximum tilt angle, and the swash plate 22 indicated by a phantom line forms the minimum tilt angle.

In the inside of the cylinder block 12, a plurality of cylinder bores 12 a are formed. In each cylinder bore 12 a, a single-headed piston 28 is accommodated. Each piston 28 has its neck where a recess 28 a is formed. In the recess 28 a, a pair of shoes 29 a, 29 b is accommodated. An outer peripheral portion 22 b of the swash plate 22 is disposed between the shoes 29 a, 29 b. As the driveshaft 17 is rotated, the swash plate 22 is rotated synchronously with the driveshaft 17. The swash plate 22 is swung, and each piston 28 is reciprocated in the fore-and-aft direction in the cylinder bore 12 a through the shoes 29 a, 29 b.

The rear side of the cylinder block 12 and the front side of the rear housing 14 are joined to each other with a valve plate 31 interposed therebetween. In the valve plate 31, a suction port 31 a and a discharge port 31 b are provided. In the rear housing 14, a suction chamber 32 is formed on the central side. In the rear housing 14, a discharge chamber 33 is formed on the peripheral side. The suction chamber 32 communicates through the suction port 31 a with a compression chamber 30 in the cylinder bore 12 a, and the discharge chamber 33 communicates through the discharge port 31 b with the compression chamber 30 in the cylinder bore 12 a.

The suction port 31 a and the discharge port 31 b are provided with a suction valve 31 c and a discharge valve 31 d, respectively. While the piston 28 is moved from a top dead center position to a bottom dead center position, a refrigerant gas in the suction chamber 32 is sucked through the suction port 31 a into the compression chamber 30. The refrigerant gas sucked into the compression chamber 30 is compressed by a movement of the piston 28 from the bottom dead center position to the top dead center position, and discharged through the discharge port 31 b into the discharge chamber 33.

In the rear housing 14, a displacement control valve 34 is placed. The displacement control valve 34 changes the tilt angle of the swash plate 22. Specifically, the displacement control valve 34 is disposed at a certain position along a supply passage 35 which allows the crank chamber 16 and the discharge chamber 33 to communicate with each other. In the cylinder block 12, a bleed passage 36 which allows the crank chamber 16 and the suction chamber 32 to communicate with each other is formed.

The opening of the displacement control valve 34 is adjusted and accordingly the pressure in the crank chamber 16 is determined depending on the relation between the amount of a high-pressure refrigerant gas drawn from the discharge chamber 33 into the crank chamber 16 and the amount of the refrigerant gas drawn out through the bleed passage 36 from the crank chamber 16 to the suction chamber 32. A pressure difference between the inside of the crank chamber 16 and the inside of the compression chamber 30 is changed and accordingly the tilt angle of the swash plate 22 is changed. The tilt angle of the swash plate 22 is thus changed. Accordingly the amount of stroke of the piston 28 is adjusted and the displacement of the compressor 100 is also adjusted.

(Suction Passage 38)

In the rear housing 14, a suction passage 38 is provided to extend therethrough for taking in a refrigerant gas. The suction passage 38 is formed in a substantial L shape having a bent portion, and an inlet port 37 is arranged at an inlet portion of the suction passage 38. The inlet port 37 is connected to a low-pressure side of an external refrigerant circuit (not shown). Through the inlet port 37 and the suction passage 38, a refrigerant gas is sucked from the external refrigerant circuit toward the suction chamber 32. At a certain position along the suction passage 38, a suction throttle mechanism 50 is provided for changing the opening of the suction passage 38.

FIG. 2 is a cross-sectional view showing the suction throttle mechanism 50 (closed state), the suction passage 38, and some other parts. FIG. 3 is a perspective view schematically showing the suction throttle mechanism 50 (opened state). FIG. 4 is a cross-sectional view showing the suction throttle mechanism 50 (full-opened state), the suction passage 38, and some other parts. FIG. 5 is a cross-sectional view along a line V-V in FIG. 4 as seen in the direction of arrows.

As shown in FIG. 2, the suction passage 38 is a space formed by making a part of the rear housing 14 hollow, and has a portion (cylindrical space) extending in the shape of a cylinder from the inlet port 37 to a bottom 38 a. In the rear housing 14, a hollow portion 42 is further provided for allowing the cylindrical space and the suction chamber 32 to communicate with each other. The suction passage 38 has a substantial L shape made up of the cylindrical space and the hollow portion 42.

The hollow portion 42 is formed by making a hole in a wall-like part of the rear housing 14 that is located between the suction chamber 32 and the portion (cylindrical portion) extending in the shape of a cylinder from the inlet port 37 to the bottom 38 a (in the part corresponding to the sidewall of the cylindrical space), so that the hole extends from the suction chamber 32 toward the cylindrical space. The aforementioned cylindrical space may be provided in the rear housing 14 after the suction chamber 32 and the hollow portion 42 are provided in the rear housing 14.

The hollow portion 42 is a space extending in the shape of a cylinder from the suction chamber 32 toward a bottom 42 a, and this space crosses the cylindrical space (the portion extending in the shape of a cylinder from the inlet port 37 to the bottom 38 a). The hollow portion 42 is formed to extend from the suction chamber 32 to a position beyond the portion where the cylindrical space is formed. In the state (the state shown in FIG. 2) where the suction throttle mechanism 50 is attached to the suction passage 38, the bottom 42 a of the hollow portion 42 is located away from the suction throttle mechanism 50 (such as a valve housing 58) (see FIG. 5), and the bottom 42 a of the hollow portion 42 faces to the suction throttle mechanism 50 with a space therebetween.

(Suction Throttle Mechanism 50)

As shown in FIGS. 2 and 3, the suction throttle mechanism 50 disposed in the suction passage 38 includes a valve body 52, a valve seat 54, a coil spring 56 (FIG. 2), and the valve housing 58. The valve seat 54 and the valve housing 58 are fit in the bent portion of the suction passage 38 so that they face to each other.

(Valve Seat 54)

The valve seat 54 has a hollow-cylindrical shape whose center is an axial line X1, and is disposed in the suction passage 38 between the inlet port 37 and the suction chamber 32 of the compressor 100. A valve hole 54 h is formed inside the valve seat 54, and a refrigerant (fluid) passes through the valve hole 54 h (in the valve seat 54). At the lower end of the valve seat 54, a seat surface 54 b is formed. The seat surface 54 b is located on a plane which is in parallel with a plane orthogonal to the axial line X1. The seat surface 54 b is provided to be closer to the inlet port 37 than the valve body 52 and restricts movement of the valve body 52 displaced toward the inlet port 37. At the upper end of the valve seat 54, four engage pieces 54 a are provided.

With an O ring 55 (FIG. 2) fit around the valve seat 54, the valve seat 54 is inserted into the suction passage 38 in the direction of approaching the inlet port 37 (in the bottom-to-top direction in the drawing of FIG. 2). In an inner peripheral surface of the rear housing 14 that forms the suction passage 38, recesses corresponding to the engage pieces 54 a are provided. The engage pieces 54 a are engaged in the recesses to thereby prevent the valve seat 54 from coming off the rear housing 14. In this state, the lower end of the valve seat 54 protrudes from the inner peripheral surface (wall surface) of the rear housing 14 where the valve seat 54 is fixed, toward the bottom 38 a of the suction passage 38, and the seat surface 54 b is located in the hollow portion 42.

(Valve Housing 58)

The valve housing 58 is a member formed as a separate body from the valve seat 54, and includes a hollow-cylindrical portion 58 a, a peripheral wall portion 58 b (guide portion), a disk portion 58 c, and a column portion 58 d (guide portion). The hollow-cylindrical portion 58 a and the peripheral wall portion 58 b have a hollow-cylindrical shape whose center is the axial line X1. The peripheral wall portion 58 b has a shape extending in the direction of approaching the valve seat 54, along the direction parallel with the direction in which the axial line X1 extends.

The peripheral wall portion 58 b is arranged to externally surround an outer peripheral surface 52 s of the valve body 52. The peripheral wall portion 58 b makes sliding contact with the outer peripheral surface 52 s of the valve body 52 to thereby allow the valve body 52 to move in a contact-separate direction (the direction indicated by an arrow AR shown in FIG. 3) in which the value body 52 is to contact or separate from the value seat 54 to thereby adjust an opening of the suction passage 38. As compared with the peripheral wall portion 58 b, the hollow-cylindrical portion 58 a is located closer to the bottom 38 a of the suction passage 38. In the hollow-cylindrical portion 58 a, a vent hole 58 h is provided.

The valve housing 58 (the hollow-cylindrical portion 58 a, the peripheral wall portion 58 b, the disk portion 58 c, and the column portion 58 d) and the valve body 52 form a valve chamber in their inside. The vent hole 58 h allows the valve chamber and the suction chamber 32 to communicate with each other. The area of the opening of the vent hole 58 h and the spring constant of the coil spring 56 or the like are changed to thereby adjust the force which is necessary for causing the refrigerant to press down the valve body 52 and open the suction passage 38. The disk portion 58 c closes the lower end of the hollow-cylindrical portion 58 a. On the outer periphery of the disk portion 58 c, four engage pieces 58 f are provided.

The column portion 58 d has the shape of a cylindrical column. The column portion 58 d is provided on the disk portion 58 c and extends along the axial line X1. A leading end 58 e of the column portion 58 d has a tapered shape gradually decreasing in the direction of approaching the valve seat 54. The column portion 58 d has a function of guiding the valve body 52 which moves in the contact-separate direction.

Specifically, the column portion 58 d is inserted in a through hole 52 h (as will be described later herein) formed in the valve body 52, and makes sliding contact with the inner peripheral surface forming the through hole 52 h of the valve body 52 to thereby allow the valve body 52 to move in the contact-separate direction (the direction indicated by the arrow AR shown in FIG. 3) while guiding the valve body 52. While the column portion 58 d in the present embodiment is formed integrally with the disk portion 58 c so that it forms a part of the valve housing 58, the column portion 58 d may be formed of another member independent of the valve housing 58.

With an O ring 57 (FIG. 2) fit around the valve housing 58 (hollow-cylindrical portion 58 a), the valve housing 58 is inserted in the bottom 38 a side of the suction passage 38 in the direction of separating from the inlet port 37 (in the top-to-bottom direction in the drawing of FIG. 2). In an inner peripheral surface of the rear housing 14 that forms the suction passage 38, recesses corresponding to the engage pieces 58 f are provided. The engage pieces 58 f are engaged in the recesses to thereby prevent the valve housing 58 from coming off the rear housing 14.

In this state, the valve housing 58 and the valve seat 54 are spaced away from each other. The upper end of the valve housing 58 (peripheral wall portion 58 b) protrudes from the inner peripheral surface of the rear housing 14 where the valve housing 58 is fixed, toward the inlet port 37 of the suction passage 38. The leading end 58 e of the column portion 58 d extends to a position located in the valve hole 54 h of the valve seat 54. In the direction along which the axial line X1 extends (the contact-separate direction of the valve body 52), the peripheral wall portion 58 b of the valve housing 58 is spaced away from the valve seat 54. The upper end (called guide end 58 t) of the peripheral wall portion 58 b of the valve housing 58 is located in the hollow portion 42. In the direction along which the axial line X1 extends, the guide end 58 t is a portion of the peripheral wall portion 58 b (guide wall) that is located closest to the valve seat 54.

(Valve Body 52) Valve body 52 is located downstream in the suction passage 38 with respect to the valve seat 54. The valve body 52 moves in the suction passage 38 along the direction in which the axial line X1 extends (the contact-separate direction to contact or separate from the valve seat 54) to thereby adjust the opening of the suction passage 38. The valve body 52 includes an outer hollow-cylindrical portion 52 a, a disk portion 52 b, and an inner hollow-cylindrical portion 52 d. The disk portion 52 b faces to the valve seat 54. The outer hollow-cylindrical portion 52 a and the inner hollow-cylindrical portion 52 d have a hollow-cylindrical shape whose center is the axial line X1, and extend from the disk portion 52 b in the contact-separate direction of the valve body 52.

At the front end of the disk portion 52 b, a seal surface 52 c is formed. The seal surface 52 c is in parallel with a plane orthogonal to the axial line X1. As the valve body 52 is displaced forward to cause the seal surface 52 c to abut against the seat surface 54 b of the valve seat 54, the valve body 52 is seated on the valve seat 54 and the seal surface 52 c closes the valve hole 54 h (suction passage 38). At the center of the disk portion 52 b, the through hole 52 h is formed that has a shape extending along the direction in which the valve body 52 is to contact or separate from the valve seat 54. The through hole 52 h is located at the upper end of an inner peripheral surface 52 u of the inner hollow-cylindrical portion 52 d.

The outer diameter of the outer hollow-cylindrical portion 52 a (outer peripheral surface 52 s) of the valve body 52 is substantially equal to the inner diameter of the peripheral wall portion 58 b of the valve housing 58. The inner diameter of the through hole 52 h of the valve body 52 and the inner diameter of the inner hollow-cylindrical portion 52 d (inner peripheral surface 52 u) are each substantially equal to the outer diameter of the column portion 58 d of the valve housing 58. The valve body 52 can be moved in the contact-separate direction while being guided by both the peripheral wall portion 58 b and the column portion 58 d of the valve housing 58. In the present embodiment, the leading end 58 e of the column portion 58 d extends in the valve hole 54 h of the valve seat 54. Therefore, at and around the time when the valve body 52 comes to seat on the valve seat 54, the valve body 52 is still supported by the column portion 58 d and thus can be moved smoothly all the time. The inner hollow-cylindrical portion 52 d has a shape extending downward from the lower surface of the disk portion 52 b. Although the inner hollow-cylindrical portion 52 d is not a requisite component, it preferably has a certain length or more so that the valve body 52 can stably move when the valve body 52 moves in the contact-distant direction while sliding in contact with the column portion 58 d.

On the disk portion 58 c of the valve housing 58, a seat 53 is provided, and the coil spring 56 (urge member) is provided between the disk portion 52 b of the valve body 52 and the seat 53. The coil spring 56 accommodated in the valve housing 58 urges the valve body 52 in the direction in which the valve body 52 approaches the valve seat 54. On the inner side of the peripheral wall portion 58 b of the valve housing 58, a stopper 59 having an annular shape is provided. The column portion 58 d extends inside the inner periphery of the coil spring 56, and the column portion 58 d and the coil spring 56 enable a stable operation of the valve body 52.

When the valve body 52 is lifted to the maximum extent to cause the seal surface 52 c of the valve body 52 to abut against the seat surface 54 b of the valve seat 54, the opening area of the suction passage 38 is the minimum area (closed state). The valve body 52 shown in FIG. 2 is seated on the valve seat 54 and the suction passage 38 generates the closed state. In the direction along which the axial line X1 extends, a portion of the outer peripheral surface 52 s of the valve body 52 that is located closest to the valve seat 54 is herein referred to as outer peripheral end 52 t. In the state where the valve body 52 is seated on the valve seat 54, the upper end (called guide end 58 t) of the peripheral wall portion 58 b of the valve housing 58 is located further from the valve seat 54, as compared with the outer peripheral end 52 t of the valve body 52.

Referring to FIG. 4, when the valve body 52 comes to be separated from the valve seat 54, the valve body 52 moves in the space between the valve seat 54 and the peripheral wall portion 58 b of the valve housing 58. The valve body 52 is moved away from the valve seat 54 while being guided by both the peripheral wall portion 58 b and the column portion 58 d of the valve housing 58. When the valve body 52 is lowered to the maximum extent and the valve body 52 abuts against the stopper 59 in the valve housing 58, the opening area of the suction passage 38 is the maximum area (full-opened state). The lower end of the valve body 52 shown in FIG. 4 abuts against the stopper 59 and the suction passage 38 generates the full-opened state. As described above, the upper end (guide end 58 t) of the peripheral wall portion 58 b of the valve housing 58 is separated sufficiently from the seat surface 54 b of the valve seat 54, and therefore, a broad communication passage 39 is formed between the seal surface 52 c of the valve body 52 and the seat surface 54 b of the valve seat 54.

As shown in FIGS. 4 and 5, in the state where the valve body 52 is separated from the valve seat 54, the communication passage 39 has a shape opened by 360° along the circumference whose center is the axial line X1. When the valve body 52 is separated from the valve seat 54, a refrigerant (fluid) flows from the inlet port 37 through the valve hole 54 h of the valve seat 54 toward the valve body 52. At this time, the tapered shape of the leading end 58 e of the column portion 58 d enables the refrigerant to smoothly flow along the shape of the leading end 58 e of the column portion 58 d, and the column portion 58 d is restrained from acting as a resistance against the flow of the refrigerant.

The refrigerant can thereafter continuously flow into the suction chamber 32 through the communication passage 39, while spreading outward in all directions orthogonal to the axial line X1 and passing through the portion between the valve seat 54 and the valve housing 58 (peripheral wall portion 58 b). The above-described features make the opening area of the communication passage 39 larger to enable the flow rate of the refrigerant to be easily increased and accordingly enable the cooling performance by the refrigerant of the compressor 100 to be improved.

In the present embodiment, the hollow portion 42 is provided in the rear housing 14 to thereby form the communication passage 39 which is opened by 360°. It is not a requisite feature to provide the hollow portion 42 in the rear housing 14. In the case where the hollow portion 42 is not provided in the rear housing 14, the communication passage 39 which is opened by 360° may not be formed. Even in this case, the column portion 58 d and the peripheral wall portion 58 b of the valve housing 58 perform the guide function. Thus, the portion of the guide means that guides the valve body 52 can be reduced in size, and accordingly the opening area of the communication passage (the space corresponding to the communication passage 39) can be increased.

Comparative Example

FIG. 6 is a cross-sectional view showing a suction throttle mechanism 50Z (full-opened state) in a comparative example. FIG. 7 is a cross-sectional view along a line VII-VII in FIG. 6 as seen in the direction of arrows. The valve housing 58 of the suction throttle mechanism 50Z has a peripheral wall portion 58 b coupled to the lower end of the valve seat 54. An upper end 58 tz of the peripheral wall portion 58 b of the valve housing 58 is located above the seat surface 54 b of the valve seat 54. In the suction throttle mechanism 50Z, the valve body 52 is moved in the contact-separate direction while being guided by only the peripheral wall portion 58 b of the valve housing 58.

In the peripheral wall portion 58 b, a through hole 52 k is provided to extend therethrough for allowing the suction passage 38 (valve hole 54 h) and the suction chamber 32 to communicate with each other. The part of the peripheral wall portion 58 b in which the through hole 52 k is not provided forms a sidewall 52 w (FIG. 7). When the valve body 52 is separated from the valve seat 54, a communication passage 39 z is formed between the seal surface 52 c of the valve body 52 and the seat surface 54 b of the valve seat 54. As shown in FIG. 7, the communication passage 39 z is formed in only the portion where the sidewall 52 w is not provided, and does not have a shape opened by 360° along the circumference whose center is the axial line X1

The sidewall 52 w is a portion for guiding the valve body 52, and also acts as a resistance against the flow of the refrigerant. It is necessary for the sidewall 52 w to have a certain strength or more for stably guiding the valve body 52. It is therefore difficult to reduce the size (surface area) of the sidewall 52 w, namely increase the opening area of the communication passage 39 z.

Second Embodiment

Referring to FIG. 8, a suction throttle mechanism 50A in a second embodiment will be described. FIG. 8 is a cross-sectional view showing the suction throttle mechanism 50A (closed state). In the second embodiment, the position of the upper end (guide end 58 t) of the peripheral wall portion 58 b of the valve housing 58 is located relatively closer to the bottom 38 a (further from the valve seat 54) as compared with the above-described first embodiment.

In the first embodiment, the valve body 52 is moved in the contact-separate direction while being guided all the time by both the peripheral wall portion 58 b and the column portion 58 d of the valve housing 58. In the second embodiment as well, the valve body 52 is moved in the contact-separate direction while being guided by both the peripheral wall portion 58 b and the column portion 58 d of the valve housing 58. In the state where the valve body 52 is seated on the valve seat 54 and the state immediately before this, however, the valve body 52 is not guided by the peripheral wall portion 58 b of the valve housing 58.

The fact that the position of the upper end (guide end 58 t) of the peripheral wall portion 58 b of the valve housing 58 is located relatively closer to the bottom 38 a (further from the valve seat 54) enables the opening area of the communication passage 39 (see FIG. 4) to be larger than that of the first embodiment. The configuration in which the valve housing 58 does not have the peripheral wall portion 58 b may also be employed. In this case, the valve body 52 is moved in the contact-separate direction while being guided by only the column portion 58 d of the valve housing 58. The opening area of the communication passage 39 can further be increased accordingly.

Third Embodiment

Referring to FIG. 9, a suction throttle mechanism 50B in a third embodiment will be described. FIG. 9 is a cross-sectional view showing the suction throttle mechanism 50B (closed state). In the third embodiment, the valve housing 58 does not include the column portion 58 d. The valve body 52 is moved in the contact-separate direction while being guided by only the peripheral wall portion 58 b of the valve housing 58.

In the present embodiment as well, in the state where the valve body 52 is seated on the valve seat 54, the upper end (guide end 58 t) of the peripheral wall portion 58 b of the valve housing 58 is located further from the valve seat 54, as compared with the outer peripheral end 52 t of the valve body 52. The above-described features make, like the first embodiment, the opening area of the communication passage 39 (see FIG. 4) larger to enable the flowrate of the refrigerant to easily be increased and accordingly enable the cooling performance by the refrigerant of the compressor to be improved.

Fourth Embodiment

Referring to FIG. 10, a suction throttle mechanism 50C in a fourth embodiment will be described. FIG. 10 is a perspective view schematically showing the suction throttle mechanism 50C (opened state). In the first embodiment (see FIG. 3), the peripheral wall portion 58 b of the valve housing 58 has a hollow-cylindrical shape. In the fourth embodiment, the peripheral wall portion 58 b of the valve housing 58 has a columnar shape, and the peripheral wall portion 58 b is divided into two portions 58 b 1, 58 b 2. Between the portions 58 b 1 and 58 b 2, an opening 58 u is formed. Two openings 58 u are formed at respective positions separated from each other by 180° in the circumferential direction of the peripheral wall portion 58 b. The valve housing 58 (the hollow-cylindrical portion 58 a, the peripheral wall portion 58 b, the disk portion 58 c, and the column portion 58 d) and the valve body 52 form a valve chamber in their inside, and the openings 58 u allow the inner space (valve chamber) of the valve housing 58 and the suction chamber 32 to communicate with each other. The openings 58 u can perform the function of the vent hole 58 h (see FIG. 3) in the first embodiment.

The above-described features also make, like the first embodiment, the opening area of the communication passage 39 (see FIG. 4) larger to thereby enable the flow rate of the refrigerant to be easily increased and accordingly enable the cooling performance by the refrigerant of the compressor to be improved.

Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the scope of the present invention being interpreted by the terms of the appended claims. 

What is claimed is:
 1. A suction throttle mechanism of a compressor, the suction throttle mechanism comprising: a valve seat disposed in a suction passage between an inlet port and a suction chamber of the compressor and formed in a cylindrical shape for passing a fluid through the valve seat; a valve body moving in the suction passage in a contact-separate direction in which the valve body is to contact or separate from the valve seat to thereby adjust an opening of the suction passage; and a valve housing accommodating an urge member urging the valve body toward the valve seat, the valve housing and the valve seat being formed as separate bodies, the valve housing and the valve seat being spaced away from each other, the valve housing having a guide portion sliding in contact with the valve body to thereby allow the valve body to move in the contact-separate direction, when the valve body is separated from the valve seat, a fluid flowing from the inlet port toward the valve body through the valve seat passing between the valve seat and the valve housing to enter the suction chamber.
 2. The suction throttle mechanism of a compressor according to claim 1, wherein the valve body has a through hole provided in a direction in which the valve body is to contact or separate from the valve seat, and the guide portion includes a column portion inserted in the through hole and making sliding contact with an inner peripheral surface of the through hole to thereby guide the valve body.
 3. The suction throttle mechanism of a compressor according to claim 2, wherein a leading end of the column portion extends in the valve seat.
 4. The suction throttle mechanism of a compressor according to claim 2, wherein a leading end of the column portion has a tapered shape gradually decreasing in a direction of approaching the valve seat.
 5. The suction throttle mechanism of a compressor according to claim 2, wherein the urge member is a coil spring, and the column portion extends inside an inner periphery of the coil spring.
 6. The suction throttle mechanism of a compressor according to claim 2, wherein the valve housing, the valve body, and the column portion form a valve chamber, and the valve housing has a vent hole formed for allowing an inside of the valve chamber to communicate with the suction chamber.
 7. The suction throttle mechanism of a compressor according to claim 1, wherein the valve body has a disk portion facing to the valve seat and a hollow-cylindrical portion extending from the disk portion in the contact-separate direction of the valve body.
 8. The suction throttle mechanism of a compressor according to claim 1, wherein the guide portion includes a peripheral wall portion which makes sliding contact with an outer peripheral surface of the valve body to thereby guide the valve body.
 9. The suction throttle mechanism of a compressor according to claim 1, wherein the suction passage is formed in a substantial L shape having a bent portion, the valve seat and the valve housing are fit in the bent portion of the suction passage so that the valve seat and the valve housing face to each other, and the valve seat protrudes from a wall surface forming the suction passage. 